About version

has a version attribute, the persistence provider must perform optimistic version checks ... mode other than NONE is specified OptimisticLockException - if the optimistic version check fails ... has a version attribute, the persistence provider must perform optimistic version checks when obtaining

ObjectDB can be used by Java Virtual Machine (JVM) languages, such as Java, Groovy and Scala. It can also be used with other languages, such as Phyton, Ruby and PHP, but currently only with their JVM implementations (e.g. Jython for Phyton, JRuby for Ruby and Quercus for PHP). A version of ObjectDB

The JPA Query Language (JPQL) can be considered as an object oriented version of SQL. Users familiar with SQL should find JPQL very easy to learn and use. This chapter explains how to use JPQL as well as how to use the JPA Criteria API, which provides an alternative way for building queries in JPA